Land and Hold Short

Recently, in the cold weather, my Warrior’s battery has barely managed one try starting the plane — any more, and it goes flat. Most recently, it happened after I’d just been flying 1.7 hours and tried to restart after a short fuel stop. I had to figure out whether the problem was the battery or the alternator (or regulator).

According to AOPA, the biggest issue facing general aviation in the U.S. is the risk of user fees. I agree with Phil Boyer that user fees could hurt GA, especially if they are per use (as in Australia) rather than flat fees (as in Canada, with one misguided exception); however, I think that there are even bigger issues facing North American general aviation. Here, on no scientific basis whatsoever, are my top five:

1. The end of AvGas: Almost nobody makes AvGas any more, it’s expensive to transport, and environmentalists rightly hate it because it’s leaded. Watch for it to get rarer and more expensive, with more and more shortages, over the next few years, at the same time as ethanol in MoGas renders it unsuitable for the few aircraft engines that could use it. The solution? Diesel engines, but they’re still expensive to install (nearly the whole cost of my plane), probably won’t ever be approved for all existing models, and do not yet have a significant North American maintenance network in place. Most old planes will have to be retired, and most pilots won’t be able to afford to replace ‘em, so they’ll retire with their planes.

2. (In)Security: It’s there, and it’s not going to go away. The general public has always been afraid of airplanes (I’ve posted in the past about how we exacerbate the problem by promoting air shows), and general aviation in particular scares them because it’s so lightly regulated. In the 2004 U.S. presidential election, one of the candidates was a GA pilot and went out of his way not to cause problems for his fellow pilots; in 2008, we probably won’t be that lucky. And the next time something bad happens, watch for GA to be the scapegoat even more than in 2001: we could be regulated right out of existence on either or both sides of the border.

3. Airport closures: New residential neighbourhoods, either on reclaimed industrial land in the city or former farmland in the country, almost always mean bad news for general aviation. Airports are useful only when they’re near somewhere you want to go, so the most useful airports are typically also the most threatened: Toronto City Centre Airport is constantly under seige from nearby condo dwellers, for example, and even little Rockcliffe Airport struggles with community noise complaints (note that both of these airports have been there since before World War II). Airports aren’t the only ones who suffer from the soccer-mom onslaught: in rural areas farmers have to deal with complaints from new subdivisions about noise and smell, hunters have to go further away to hunt, and so on.

4. Maintenance: Most of the GA fleet is, and will remain, old — very few of us can shell out $300K-$1M for a new light plane, so we have to settle for spending $20K-$150K on something older. It would take only a couple of expensive Airworthiness Directives from the FAA or Transport Canada to knock a huge part of the fleet out of the sky by requiring a repair worth more than the planes’ resale value. Furthermore, the shops that maintain these planes for us often operate on a shoestring, billing much less per hour than an auto shop, and in the U.S. a few of them are starting to refuse to work on older planes for liability reasons (U.S. law protects manufacturers from being sued once the planes are a certain age, so the shop would be the only one to go after in a crash).

5. User fees: We’ve been paying these in Canada for a while now, and since they’ve remained low and fixed (thanks to COPA), they don’t seem to have had any impact at all on GA. However, that could change easily. If either Canada or the U.S. introduced a pay-per-use system, flying could quickly become too expensive and/or too dangerous for most GA owners. For example, if you had to pay $100 each time you filed IFR, scud running might become a bit more tempting; if you had to pay $25 for a weather briefing, you’d be less likely to talk to a specialist about icing. Realistically, I don’t think this is as big a threat as the others, but I’m still grateful that COPA and AOPA (I’m a member of both) are looking out for our interests.

It’s been four years, almost to the day, since I bought my 1979 Piper Warrior II, and it’s time for another annual inspection (I’ve moved it up from May to December to avoid missing good flying weather, so this is the second annual in 2006).

So far, everything looks good, but this is not going to be the stereotypical owner-pilot annual inspection progress posting. Instead, I wanted to mention that while people refer to the Cherokee as a relatively simple plane, this is the first year that it has actually seemed simple to me.

I was able to talk to my AME (mechanic) on his level instead of forcing him to stoop to mine, and I knew — not just academically, but from real experience and sense of touch — what nearly every exposed part was and how it was supposed to work. A couple of weeks ago, I prepared a short spreadsheet of the extra work I wanted done and my estimated hours for each item, and the AME agreed that my estimates were in the right ballpark. Today we walked through the inspection snag sheet quickly and efficiently. I approved a small amount of extra work based on the findings during the initial inspection, then drove my altimeter down to the instrument shop for its biennial recertification.

It really is a different experience when you understand what’s under the cowling and behind the interior panels. Early bush pilots had to take care of their own planes, but from what I understand, a modern commercial pilot flying (say) a Cessna 182 is not even allowed to change her own oil unless she also happens to be an AME. I’m not sure this is a good thing: maybe a month or two helping on a shop floor (fetching buckets of propwash or what-have-you) would be a good addition to the commercial pilot syllabus.

On most airplanes, you can trim the elevator by turning a wheel or crank that sets a tab — a flap on a flap — that then redirects the airflow to hold the elevator or stabilator at a certain angle of attack. Elevator trim is fairly important, since it saves you from having to hold constant pressure on the yoke to keep the plane from diving to the ground or going nose up and stalling. Fancier planes also have rudder and aileron trim (the Warrior has a fake rudder trim that’s really just a spring in the control system).

Since I bought my Piper Warrior II in December 2002, the elevator trim wheel has been surprisingly hard to move. Sometimes I almost get used to it, but then I fly another plane and notice that the wheel does not require 20+ lb of force to turn. At every annual inspection, I’ve squawked the trim, and mechanics have replaced the cable, replaced the pulley, and tried various lubricants. It always seemed a bit easier afterwards, but then soon went back to its old self.

This year, I squawked the trim once again, but the mechanic wasn’t satisfied just relubing; instead, he decided to examine the trim tab itself, and he noticed that when you turn the trim wheel, the tab flexes, but that the hinge has seized up with corrosion and does not seem actually to move. I imagine that it has been moving some — since it also acts as an anti-servo tab, the plane would be tricky to control otherwise, and I’m sure that I verified at least some movement on every preflight — but it’s still strange to think that I’ve been flying single-pilot IFR with no autopilot and trimming my plane by flexing aluminum through brute force alone. Man vs. machine, indeed.

Nav Canada has decided to go ahead and charge small aircraft a daily fee of $10.00, starting in March 2008, for using any of Canada’s seven busiest airports (and the Vancouver harbour water aerodrome) — that’s on top of any landing fees, etc. charged by the airport authorities. Here’s their announcement. Here’s my response from last February, which still represents my opinion about the charges.

Nav Canada did decide to exempt aircraft from the fee when they divert to one of the major airports as a weather alternate, and they will not begin phasing in the fee this year as originally planned (unless I didn’t read the announcement carefully enough). Sadly, I think that this move may be enough to kill off the rest of the private aviation community at CYOW, ending a tradition that began in 1928 when the Ottawa Flying Club founded the airport.

Niss, who flies out of Barrie Airpark (CNA3), left this comment on my posting Should I buy or rent? (divide all prices by about 1.2 to get US dollars):

I am looking to buy a share in an aircraft. Right now at my local airport (CNA3) there is a 1966 Piper Cherokee 140 on the ramp. The owner is looking for $32500 and I am told that he might be interested in selling off 25% Shares. TTSN: 5693 HRs SMOH: 1917 HRs, cylinders were redone 400 hours ago. The broker that is selling it is my old boss and mentor at the airport, so I know the salesman and the owner are reputable. Also I am a student, am looking to go on to bigger and better things including my CPL and other rateings. What do you guys think this animal would cost in maintenace fees, etc? Would you say this is a wise decision for a student?

Niss - that sounds like a reasonable starter aircraft for VFR. If you want to go on and get your instrument rating, you should know that the panel is probably not in the standard T arrangement, unless someone has had it redone; you might also need to make some changes to the panel and add an alternate static air source if the plane is not currently IFR-ready. Neither of these should be a deal killer, but it’s good to be aware. Go for a test flight in the plane (you should pay for the gas, and the owner or broker should be with you) and see how you like it.

Before you plunk down about CAD 10K (including tax) for a 25% share, you need to have a thorough prepurchase inspection done by a mechanic who has never worked on the plane — that might mean bringing someone in for the day from Brampton, Markham, Peterborough, or another city nearby. Expect to spend at least CAD 1K on the inspection, maybe more if there are any areas of concern. Obviously, it would be nice to get all the 25% partners together first so that you have to do the inspection only once and can split the cost — otherwise, each will have to do his or her own inspection. A proper prepurchase will take a full day and involve a detailed review of the logbooks (including airworthiness directives and service bulletins), removing the cowling and all inspection plates, checking compressions, looking for corrosion inside the wings, etc. The plane will probably be put up on jacks, and if there are any concerns, the seats might come out as well to allow better access to the interior. You should also review the logbooks yourself to see how often the plane has flown (if it flies less than 100 hours a year, look at it carefully; if it flies less than 50, be concerned; if it flies less than 25, be *very* concerned), whether there is any damage history, and how often parts are replaced. When’s the last time the vacuum pump was replaced, for example? How old is the battery? How old are the tires? Are the gyros getting elderly? This might be too much to worry about for your first plane, but you can bet I’ll be checking if or when I buy my second — even if the individual parts are relatively inexpensive, it gives you a good idea of how well the plane has been maintained.

Remember that the time on the engine has a lot to do with the value of the plane. Including removal, shipping, and reinstallation, an engine overhaul for a Lycoming O-320 costs at least CAD 25K, maybe more like CAD 30K. Is the engine on this plane just about run out (2000 hours)? Has the engine been giving trouble and getting a lot of top work (new cylinders)? Are the compressions OK? The mechanic can help with that. Many people believe that a half-time engine (~1,000 hours) is the best deal — a brand-new overhaul done just to sell the plane might be shoddy, while a run-out engine will require you to take the time to do the overhaul and break in a new engine. Likewise, beware of any plane sold with a fresh annual — that has no value to you, since the seller will probably defer any marginal items.

Expect all the partners combined to spend about CAD 5K/year on maintenance, excluding engine reserve, if the plane is in good condition — that includes replacing radios, pumps, tires, batteries, starters, etc. as they fail. The plane will also need to be painted every decade or two, at a cost of over CAD 10K Some AMEs will let you help with the maintenance, reducing the cost a bit, but whether that’s a reasonable trade will depend on how much your time is worth. The problem is that there’s a lot of variability — you might pay $2,000 one year, and $8,000 the next. You’ll spend about $2,000/year on insurance, given the low airframe value, and gas and oil will depend on your flying (estimate about CAD 35/hour for gas, depending on where you buy it). Parking will depend on where you decide to keep the plane — you’ll want at least an electrical plugin if you plan to fly in the winter. A hangar can be expensive, but also much more convenient (and you can split it four ways).

From aviation pundits with deadlines to meet and empty pages to fill, we hear a lot about the dangers of losing a vacuum pump (and consequently, attitude indicator and directional gyro) in IMC, and why IFR pilots need to (a) practice partial panel flight a lot, and (b) have a backup vacuum pump or electric AI.

As I’ve mentioned before, while it’s possible to find a couple of fatal accidents every year caused by loss of the vacuum pump in planes with retractable gear during a (legal) IFR flight, it is extremely difficult to find any in planes with fixed gear. In fact, I had failed to find any at all during my initial research. So thanks to Paul (N9002F) for drawing my attention to two from the NTSB files:

MIA98FA045

A Cessna 172 near Raleigh-Durham, NC on Christmas Eve, 1997

ATL91FA067

A Piper Cherokee near Hamilton, NC on March 18, 1991

A full report is available for the Raleigh-Durham crash, while only a summary is available for the Hamilton crash, but they both make interesting reading. To start with, as a brutal irony, both planes were equipped with functioning backup vacuum pumps, precisely what’s supposed to prevent this kind of accident. Even more ironically, it looks like the backup pumps themselves might have contributed to the accidents, at least in a small way.

Too much diagnosis, not enough flying?

In the first accident, the problem took place right after takeoff into low IMC. The pilot diagnosed the problem immediately and reported a vacuum failure to ATC, and then (as the NTSB determined from the wreckage) selected his standby pump. After that, the plane continued in a turn until it hit the ground.

The NTSB found that both the main and standby vacuum pumps were actually working and the gyros were undamaged — in fact, it is most likely that there was no failure at all. They also tested and discounted the possibility that a tube might have worked loose in flight, causing a (false) vacuum warning light on the panel. Furthermore, the flight lasted only 2 1/2 minutes, while it would have taken about 10 minutes for the gyros actually to spin down after a failure.

Why did the pilot report a vacuum failure? Could it simply have been a case of the spatial disorientation (his body disagreeing with the instruments), followed by the distraction of trying to troubleshoot a non-existant vacuum problem and select a standby pump? In my experience hand-flying my Warrior in IMC, initial climbout is by far the most difficult part of IFR flight, since the plane naturally wants to turn, and you have to keep strong rudder pressure to stay on course. Even the slightest distraction, like a radio call, and throw your course off 10-15 degrees if you’re not careful or a bit out of practice — in this case there was a lot more distraction than that, and sadly, having a backup vacuum pump to fiddle with (instead of flying the plane to a safe altitude first) probably made things worse.

Backup is not primary

The Hamilton, NC report does not give as much information as the other one, but it does mention the following:

• the pilot reported a pitot-static failure as well as a vacuum failure
• the pilot decided to continue the flight using the backup vacuum pump (and, presumably, no altimeter, VSI, or airspeed indication!!!)

After 28 minutes of erratic flying, the pilot finally lost control of the aircraft. The brief report does not indicate whether the backup vacuum pump also failed, but it does mention “improper use of equipment that affected the operation of the standby vacuum pump”. Did having a backup vacuum pump give the pilot the confidence to continue the flight?

Tentative conclusions

So neither of these is a clear case of a pilot losing control of a fixed-gear plane because of a vacuum pump failure. In the first case, both the primary and backup vacuum pumps (as well as the gyros) were all working properly, and we cannot know why the pilot thought otherwise; in the second case, the pilot was also facing a pitot-static failure, knocking out most of the panel, but decided to keep on flying for a half hour in IMC.

Are fixed-gear planes just a lot easier to fly partial panel, then? That’s what a 2002 ASF/FAA study suggests. Two groups of pilots were tested in actual aircraft rigged up to allow unannounced gyro failures — one group was tested in a Beech Bonanza (retractable), and the second group was tested in a Piper Archer (fixed gear). The results? The Archer pilots did a lousy job diagnosing the problem — it took them nearly 7 minutes on average to realize that something was wrong — but every single one kept control of the aircraft. The Bonanza pilots, presumably a much more experienced group of complex-aircraft pilots, diagnosed the problem faster — in less than four minutes, on average — but couldn’t all control their planes flying partial panel, and 4 out of 16 were judged to have crashed (i.e. someone without a hood had to take the controls).

I have two tentative conclusions from all of this, though I am far from an expert:

1. While installing an aftermarket backup vacuum pump in a fixed-gear plane might not hurt, it probably won’t help either, and might even be a dangerous distraction — investing the same amount of money in recurrent training, better maintenance, etc. probably makes more sense.
2. It’s a lot easier to maintain control of a fixed-gear plane flying partial panel, so upon losing gyros or the vacuum pump in a retractable, maybe checklist item #1 should be drop the gear to add drag and make the plane more controllable (if you’re above gear-extension speed, let that be the mechanic’s problem after you land). After all, the 25% fatality rate for retracts in the ASF/FAA simulation makes for lousy odds.

I’ll look forward to comments from people with other interpretations and suggestions, especially since I fly only fixed gear myself.

This morning, I read a CBC story about a control problem on an Air Canada Jazz Dash-8 flying from Kingston to Toronto on 2 September 2004. From the story, it was pretty hard to figure out what had actually happened, especially given statements like these:

• “It took the strength of two men to steady the control column of an Air Canada Jazz flight veering dangerously out of control” sounds like directional control problems — jammed aileron? asymmetric flaps?
• “pilots struggling to gain control of the plane from the moment after takeoff” directional control?
• “The control column, a stick used to manoeuvre and control altitude, was forcing the plane’s altitude higher as the craft continued to pick up speed” sounds like excessive up trim, but then why would the plane be picking up speed if the nose were up?
• “loose nuts caused bolts in the plane’s elevator spring tab - a part of the aircraft that helps maintain control - to move out of place and throw the plane’s balance and control out of whack” OK, then it’s elevator trim

I didn’t feel much better informed after reading the article, so I hunted down the actual TSB report. It makes terrifying reading, not because of the trim-control problem (as troublesome as that was), but because of the risk of catastrophic structural failure.

As far as I can understand from a quick reading, the Dash-8 has elevators that can move separately on the left and right sides, and each has its own trim tab — the left and right trim tabs have to be balanced with weights so that one doesn’t pull more than the other. When the incident plane was in for painting a while before the accident, the tabs were rebalanced. The TSB’s best guess is that the AME left the bolts loose on one side in case the weight needed to be removed for more balancing, and forgot to tighten them afterwards.

Eventually, the weight fell off, leaving the tabs badly out of balance. As the Dash-8 accelerated for takeoff from Kingston, it sought to trim nose-high. The pilot flying (first officer) noticed that very little pressure was required to lift off, and soon both pilots were pushing forward hard to maintain airspeed, even with full nose-down trim. After running through some checklists, the captain disconnected the copilot-side trim (I think — this part is a bit hazy), and then was able to trim the plane for cruise using controls on his side. Althought they had declared an emergency 30 seconds after takeoff, they decided to continue to Toronto (about a half hour away) rather than landing at CFB Trenton between Kingston and Toronto.

I can understand their decision. After all, trim is mainly just a convenience for the pilots, to save us having to push or pull the yoke constantly during flight. On such a short flight, and with one of the independent trim systems (apparently) working, why not just continue the last distance into Toronto, rather than dumping up to 50 passengers on the tarmac of a military base in the middle of nowhere?

Unfortunately, things could have turned out very badly. Because of the weight imbalance, the two elevators were exerting different forces — one was trying to push the nose down, and one was trying to pull it up. According to the TSB report, this caused a twisting force on the vertical stabilizer close to its structural limit. That reminds me of the force that snapped the tail off American Airlines flight 587, though the cause was rudder oscillations, in that case. In hindsight, we know that that was the real danger of the flight and that the trim problem was only a sympton.

If the flight crew had known the real risks, I don’t doubt that they would have set down in Trenton without a second’s thought. In my own flying, I’ll try to keep in mind that any anomaly I can actually detect may just be the tip of a very large iceberg.

Back in July 2005 (updated in September), Philip Greenspun published a detailed owner’s review of his factory-new Cirrus SR20, the 200 hp (cheaper) sibling of the Cirrus SR22. Philip has flown his plane pretty seriously around a huge part of the continent (including the Canadian arctic), and has a long list of both the good and bad aspects of it. There are dozens of annoyances — large and small — that you’d never know about after reading a glossy magazine review written on the basis of a single test flight.

Philip also speculates about the actual safety value of the chute. In his opinion, most or all of the cases where people have pulled the chute and survived would have been survivable in a non-chute equipped Piper or Cessna, while in the cases where the chute really was necessary, it failed and resulted in a fatal accident. I don’t know how accurate this analysis is, but it’s an interesting perspective, especially coming from a Cirrus owner.

This page is highly-recommended reading, even if (like me) you cannot imagine ever being able to afford a factory-new plane. The 6-8 week, USD 10,000/year annuals — while still under warranty — are certainly an eye-opener. I wonder how much he’ll pay for maintenance when the plane is a little older and the warranty has expired. It sounds like a pretty nice plane, though, on balance, and I certainly wouldn’t turn one down.

Update: WordPress tells me that this is my 100th post. Whoopie!

Update 2: I went for another test flight on Friday, and the problem is fixed.

When you land after a flight, do you know — within a gallon/a few liters — how much fuel your plane should take? Some people always take off with full tanks and limit their legs to 2-3 hours, so they figure they never have to worry.

On Tuesday, I took my Warrior for its second post-maintenance test flight. I started with full tanks, flew for 2.75 hours at 75% power, then filled up again. The plane took 146 liters of fuel, over 50% more than expected, indicating that I landed with less than 45 minutes of fuel remaining. Upon closer investigation, there was some blue staining on the wing and a bit of streaking coming from under the left side of the cowling. My new fuel pump was leaking, throwing fuel overboard as I flew. I probably leaked fuel on my first flight as well, but since I didn’t start with full tanks, it was harder to be certain (I mentioned my concern to my AME then, but we saw no evidence of leaks inside the cowling).

I’m glad that I insisted on a second test flight before making the 800 nm trip to Atlanta, but I’m also glad that I routinely track my fuel consumption and know what to expect at the pump — it’s as important as being able to read the panel instruments during flight. Unlike a Cessna (with its “both” fuel setting), my Piper would have warned me of a problem when the first tank ran dry, giving me a few minutes to land with the remaining tank, but fortunately it didn’t come to that. A new fuel pump will arrive by courier tomorrow (Thursday) morning from the engine shop.

The engine finally came off my plane earlier this week, and it should be on its way to Halifax today for a complete teardown and inspection after my lightning strike in July. I snapped a few cell-phone pictures while I was in the shop.

The first photo shows the propellers from a twin that was forced to do a gear-up landing after both the regular and manual gear extension failed — without the gear, the spinning propellers hit the pavement on landing. The pilot was smart enough to land the plane normally rather than trying to slow down and stop the props first — the props aren’t pretty, but the pilot’s unhurt and the plane, despite some damage, will fly again (hopefully before late fall).

The second is a front view of my magic magnetic engine, with the propeller and cowling removed. If you’re not used to looking at airplane engines (because, say, you rent planes that have only tiny oil-filler doors), the first thing you should note are the huge cylinders, compared to what you’d find in a car engine. Personally, I’m a bit concerned with what looks like damage on the prop spinner plate (I hadn’t noticed it when I was taking the picture).

The third is a view of the accessory drive on the back of the engine — there are various attachments there to allow the engine to spin things that, well, are supposed to spin, as well as room for other toys. The white thing in the middle is the oil filter, which gets replaced with every 50-hour oil change. One of the first things a new private owner-pilot learns is how to cut the safety wire, remove an old oil filter, cut the filter open to look for metal, attach a new filter, and safety wire it. On my plane, it’s possible do all of that without even taking off the cowling.

The dark thing just to the right of and slightly lower than the oil filter is the right magneto, which spins around to generate power for the spark plugs — there is a wire from the magneto going to one plug on each of the four cylinders (the left magneto also has a wire to a separate plug in each of the cylinders, for redundancy). Magnetos are maintenance hogs, and sometimes need to be rebuilt every few hundred hours, but fortunately the costs are not too high.

The grey, red, black, and white thing to the right of and slightly above the oil filter is the vacuum pump, which spins around to create suction to drive the gyros in the attitude indicator and heading indicator. Dry pumps like this one last 1,000 hours on average, but can fail at any time; even worse, unlike most parts, they give no warning — they go from 100% to 0% in a split second. Fortunately, I cannot find a single case of a fatal crash due to a vacuum pump failure in IMC on a fixed-gear plane flying IFR (the drag of the gear makes the plane easier to control), but there are many cases for retractables. Note to self: after losing vacuum pump in a retractable-gear plane, step #1 is lower the gear.

Here’s a close-up picture of the engine’s data plate (still can’t read it, though), and the carburetor. You know that my O-320 engine has a carburetor because of the bare “O-” prefix; if it were fuel injected, it would have an “IO-” prefix. Airplane engines almost universally use updraft carburetors, mounted underneath the crankcase — I’m not sure if there’s a good mechanical reason for that, other than avoiding having a hump sticking up in the middle of the top of the cowling. The throttle lever in the cabin pulls a wire around a series of pullies to a control on the other side of the carb (as does the mixture lever, I think). For some reason, the carburetor is much cleaner-looking than the rest of the engine.

That’s it for now. I’ve been up twice in a rental Cessna 172 to keep current, and hope to be flying my own plane again before the end of September.

I’m going to be grounded for a long time — possibly a few months — so I might not be posting much to this blog. After reattaching my overhauled and tested propeller, the shop was unable to complete a compass swing with either of two different compasses. It turns out that my plane has become heavily magnetized from the lightning hit (which I am now fairly certain happened while the plane was parked). A compass will deflect heavily towards the front part of the plane anywhere a few feet of it.

The good news is that Cherokees are mostly aluminum (and the firewall is stainless steel), so the problem is localized. Planes with steel frames, like the Mooney or most rag-and-tube planes, are extremely difficult to degauss, and are sometimes scrapped after become magnetized. In my plane, the main steel structures that could be magnetized are the engine mount, the crankshaft, and the nose strut, so the plane is probably repairable, though the insurance company may still decide to write it off.

More importantly, though, since the plane is unusually heavily magnetized, it’s almost certain that a strong electrical current passed through the engine block. That means that the engine has to be removed from the plane, shipped to Toronto, and completely disassembled and magnafluxed. Depending on how busy the shops are, I might not see my plane for a few months. I’m grateful right now that I have a helpful insurance broker who’s dealing with the adjuster on my behalf, and I’m also grateful that I took the picture of the prop that I published here earlier.

I’m still AOG, 9 days after discovering evidence of a minor lightning strike. Other than the depolarized magnetic compass, the only damage from the strike is a tiny blister at the end of the prop, easily within tolerances for filing out (see photo). However, because of the amount of heat involved, the prop had to go to Mississauga for hardness testing at Hope Aero (one of Canada’s three prop shops).

Hope’s testing confirmed that the propeller is still safe (good news), but it needs an overhaul and rebalancing (bad news), and won’t be ready until around 10 August (worse news). I fly all year, but summer is the time for the whole family to fly together, laughing at the cars stuck behind campers and construction on the highways below — it was a long drive from Ottawa to Sault Ste. Marie and back earlier this week.

[Update #1 below]

The last time I flew was Wednesday 13 July, for my IFR flight test renewal. I arrived at the airport early this morning for a quick business flight to Toronto and found two things wrong with the plane:

1. there was a small but very strange-looking nick on one of the propeller tips; and
2. the magnetic compass was indicating north, but the plane was pointing southwest

I taxied the plane around in a circle, and the compass indicated within 30-60 degrees of north no matter which direction the plane was pointing. I had to scrub the trip, apologize to my customer, and plan on joining the meeting by speakerphone.

Just before I left to head back to my home office, the owner of our local shop arrived and came out to take a look — the first thing he noticed was that corner of the propeller tip was not nicked but melted, as you could see both from the shape of the metal and from the slight paint blistering around it. That, combined with the apparent demagnetization of the mag compass, suggests that the plane took a lightning strike. We looked around, but couldn’t find any other damage (usually there’s an exit mark somewhere on the airframe, especially near the tail).

After investigation and careful consideration, I’m fairly certain that the prop strike happened on the ground, and not during my previous flight on 13 July. In particular, the damage was on the higher prop tip (as the plane was parked), we were over 25 nm from the nearest storms and in VMC during my 13 July flight (with a designated flight test examiner on board, no less), and a line of very severe thunderstorms passed through Ottawa a few days before I discovered the damage, with lightning hitting one man in a Kanata parking lot.

More info

I just stopped typing this post to take a phone call from my shop. One of the mechanics called Sensenisch (the propeller’s manufacturer), and Sensenisch said that after a lightning strike the hardness of the metal for 18 inches or so of the blade can change — it looks like the propeller might be coming off the plane and heading to Carp for non-destructive testing, and I might be on the phone to the insurance company. Next to total structural failure or a fire, a broken propeller blade is just about the worst thing that can happen in flight, so I’m not planning to play around with this one.

Update #1: Friday 22 July

The propeller is off the plane and ready to ship out to Toronto today for non-destructive testing — it wasn’t possible to test it in Carp. Everything else looks fine — I went to the airport today, and the avionics and electronics all worked correctly. There’s no exit mark on the fuselage, so we suspect that the lightning just nicked the propeller rather than travelling through the whole plane. Still, I’m AOG until at least late next week, at the height of summer-trip season.

While I was testing, my daughters were out on the field rating each touch-and-go by the four planes in the circuit by holding up from 1 to 10 fingers each. I hope that the pilots were all keeping their eyes forward, especially 150 pilot who bounced three times like a stone skipping across water — I think he got a 1 or a 2.

That’s how my plane has been for a full week now, in the shop, waiting for parts to arrive from Piper via a supplier in Memphis via a second supplier in Montreal. Owners tend to say that the annual is the most unpredictable part of aircraft ownership — after all, it’s pretty straight forward to predict how much gas you’ll burn, how much your insurance will run, how much parking will be, how much your new Garmin 530 will cost installed (just dreaming), etc., but nobody knows whether the bill after an annual inspection will be US $1,500 or $15,000 (fortunately, mine have always ended up well in the first third of that range so far).

In fact, the annual inspection itself is very predictable — it takes about 25-30 hours for an experienced mechanic to run through the full Piper Warrior II annual inspection list properly, and maybe a couple more hours for run-of-the-mill AD and SB inspections. It’s just that most of us don’t have our (private) planes looked at in detail any other time of the year unless something is obviously broken, so it’s the annual inspection that finds most of the hidden problems. I’m considering adding an unofficial semi-annual inspection — maybe 4 hours in the shop late in the fall, when I need to change the oil and jack up the plane to get the wheel fairings off anyway. Just taking off the cowling and propeller spinner and letting the guys in the shop poke around for a few hours might find a lot of small problems before they become big ones.

After all, we get the family minivan inspected twice a year, and I can just pull over to the side of the road if something breaks on it.

The annual inspection for my Warrior is approaching.

As I’ve mentioned before, as a Canadian private aircraft owner, I have the final responsibility for determining that the annual inspection has been completed. In the U.S., on the other hand, it’s not the private owner but an Inspection Authority (IA) who makes that determination and signs a logbook entry returning the plane to service after the inspection. In both countries, of course, the pilot is ultimately responsible for airworthiness before each flight, no matter who has written and signed what in the logs.

In Canada, the Aircraft Maintenance Engineer (AME) performing the annual inspection will typically follow CAR 625, appendix B: part 1 lists a set of standard inspection tasks for any small airplane, such as testing cylinder compression or the torquing and safety wiring of propeller attachment bolts. However, most aircraft manufacturers also publish a customized inspection list for each aircraft, that goes into more detail and includes additional tasks (unfortunately, the manufacturers’ inspection lists are rarely, if ever, available free online).

I’m skipping the 100 hour/annual inspection here, since it isn’t all that different than the generic one in the CARs (aside from a bit more detail). What is more interesting is that the checklist for the PA-28-161 Piper Warrior II includes tasks for 50 hours (i.e. at each oil change), 500 hours (~4-5 years), and 1,000+ hours (~8-10+ years), all inspections not specifically covered in the CARs and not necessarily familiar to owners. I don’t agree with all of these — for example, I’m not automatically going to recondition a fixed-pitch propeller at 1,000 hours if it’s still in excellent shape — but overall, these look like intelligent recommendations, and I’m going to try to make space for them in my maintenance planning. At best, I might avoid a forced landing or worse; at a minimum, I’ll be able to pass on a better-maintained plane to the next owner, and will be able to hold my head up during the prepurchase inspection.

The 50 hour inspection

This one looks huge, but most of the tasks are simple ones, and a good number qualify as elementary work (I’ll post on that in the future). Some of these are things any pilot would do before every flight, such as checking the tire pressure, oleo extension, and alternator belt, and others are part of a normal oil change, like draining the sump or cleaning the plugs. Because my Warrior is blessed with a fully-opening cowl (rather than just a tiny oil door), I can also perform a good visual inspection of the engine, hoses, sparkplug leads, and engine mount before every flight. Still, there’s a lot here that is not part of my normal 50-hour oil change. If I’m changing the oil anyway (say, in the late fall), and already have the plane up on jacks to remove the nosewheel fairing, I think it might make sense to pay for 2 hours or so of an AME’s time to perform the other tasks in this list. It looks like a relatively easy way to maintain a safe plane, and a lot less expensive than the questionable fairy-dust-style safety expenditures many owners make, like backup vacuum pumps (for fixed-gear planes) and traffic alerting systems.

• Inspect [propeller] spinner and back plate for cracks.
• Inspect [propeller] blades for nicks and cracks.
• Remove and inspect engine cowling for damage.
• Drain oil sump.
• Clean suction oil strainer at oil change. Inspect strainer for foreign particles.
• Clean pressure oil strainer or change full flow (cartidge type) oil filter element. Inspect strainer or element for foreign particles.
• Inspect oil lines and fittings for leaks, security, chafing, dents, and cracks.
• Fill engine with oil per information on cowl or service manual.
• Inspect spark plug cable leads.
• Inspect rocker box covers for evidence of oil leaks. If found, replace gasket, torque cover screws 50 inch-pounds.
• Inspect condition of carburetor heat air door and box.
• Inspect all air inlet ducts and alternate heat duct.
• Remove, drain, and clean fuel filter bowl and screen. (Drain and clean at least every 90 days.)
• Inspect condition of flexible fuel lines.
• Inspect exhaust stacks, connections and gaskets. Replace gaskets as required.
• Inspect engine mounts for cracks and loose mountings.
• Inspect condition and tension of alternator drive belt.
• Inspect security of alternator mounting.
• Check condition and security of hydraulic line and fluid in brake reservoir; fill as required.
• Reinstall engine cowl.
• Check landing, navigation, cabin and instrument lights.
• Inspect battery, box and cables (Inspect at least every 30 days). Flush box as required and fill battery per instructions on box.
• Remove, drain, and clean fuel strainer bowl and screen. Drain and clean at least every 90 days.
• Lubricate [fuselage and empennage] per lubrication chart.
• Check emergency locator transmitter battery replacement date and transmitter for operation.
• Lubricate [wing] per lubrication chart.
• Inspect oleo struts for proper extension (N-3.25 in./M-4.50 in.). Check for proper fluid level as required.
• Check tire pressure. (N-30 psi, M-24 psi.)
• Lubricate [landing gear] per lubrication chart.
• Inspect all hydraulic lines and attaching parts for security, routing, chafing, deterioration, wear, and correct installation.

The 500 hour inspection

The 500 hour inspection includes only three tasks not already in the 100 hour/annual inspection:

• (400 hours) Remove rocker box cover and perform a valve inspection.
• Remove and flush oil radiator.
• Replace auxiliary vacuum pump.
• If installed, replace central air filter.
• Clean and lubricate stabilator trim drum screw.

I have my stab trim screw cleaned and lubed regularly because it becomes stiff in cold weather, but I can find no record of the oil cooler ever having been removed and flushed — any gunk caught in it can circulate back into the cylinders, wearing them down and forcing an early overhaul; this year, I plan to have this work done as cheap insurance for my engine. I don’t have an auxiliary vacuum pump in the plane, only the main engine-driven one.

The 1,000+ hour inspection

There are only a few 1,000+ hour tasks:

• Recondition propeller.
• Replace magneto.
• Overhaul or replace engine driven and electric fuel pumps.
• (2,000 hours) Complete overhaul of engine or replace with factory rebuilt.
• Replace engine driven vacuum pump.
• Clean and lubricate all exterior needle bearings.

OK, now it’s time to be realistic. I am not going to replace my engine at 2,000 hours if it’s still going strong. In fact, I think that doing so would actually be more dangerous — the only forced landing I’ve ever seen happened right after a new engine was installed, because the shop attached something incorrectly; two other local forced landings I’ve heard about had similar causes. As long as my compressions are good and there’s no metal in the oil filter, I’d rather stick with an engine that has all its bugs shaken out than a new, unproven one. The vacuum pump, on the other hand, is cheap to buy (a few hundred dollars) and easy to install (about 30 minutes of an AME’s time) — I’ve already had one fail on me, and preemptive replacement here might make sense. I’ll have to think about that one.

Just in case anyone has the mistaken idea that I — who, as a teenage boy, preferred reading books to fixing cars — actually know much about nuts-and-bolts (so to speak) of maintenance, I’ll finish with a simple question: What’s a needle bearing?

Mike Busch has written a column about annual inspections in the U.S., especially about understandings and misunderstandings among U.S. IA’s (inspection authoritiesI think) — many US IAs think that they are a kind of police force responsible for keeping unsafe planes on the ground, and many US owners think that IAs can hold their planes hostage by squawking them.

In the U.S., after an annual inspection, the IA signs off that the plane is airworthy (or gives a discrepancy list to the owner). In Canada, as far as I understand the regs (and as my AME has explained them to me), the AME does not even have to write that the plane passed or didn’t pass an annual inspection, at least not for small, private, piston-powered aircraft. Here’s the exact language from CARS Standard 625, Appendix B — Maintenance Schedule:

(6) Pursuant to CAR 605.86(2), the schedule is considered to be approved for use by owners of small non-commercial operation aircraft and all balloons. Owners need only to make an entry in the aircraft technical records that the aircraft is maintained pursuant to the maintenance schedule.

In other words, I could grab the maintenance schedule, research the ADs, make a list of tasks (inspections and repairs), and take the plane to three different shops, each of which does a third of the work. I would not have to tell any of those shops that the work was part of an annual inspection — each one would simply write what it did into the logbook. Once I was satisfied that everything required for the annual inspection was finished, I would simply return the aircraft to service, and my annual inspection is finished.

In practice, of course, I wouldn’t do things that way. I value my the experience and knowledge of my AME, and I want him to take an active role in keeping the plane safe. And, of course, with or without an IA’s signature, the final responsibility for airworthiness will always lie with the pilot in command.

Sacramento Sky Ranch, which sells airplane parts, has an RSS 2.0 feed dedicated to light aircraft maintenance, including pictures and even sound.

There’s lots of great stuff here, from the sound a cracked cylinder makes when you flick the fin (yes, there’s a WAV file!) to why an oil/air separator to an engine is (in their opinion) an incredibly stupid idea. It’s aimed mainly at mechanics, but there’s good information for the owner/pilot as well. I’ve subscribed.